Mobile phones with digital cameras are dominating worldwide mobile device markets. According to market statistics and forecasts, by 2018, annual smartphone shipments are expected to grow to 1.87 billion units, and over 80% of all mobile phones will be arriving to customers with embedded digital cameras of growing quality and with quickly expanding set of features. These shipments will be adding to an already massive audience of approximately 4.5 billion mobile phone users and almost seven billion mobile subscribers. Annual sales by suppliers of phone cameras to mobile phone manufacturers for embedding into smartphones and feature phones is expected to exceed 1.5 billion units per year.
The volume of photographs taken with phone cameras is also rapidly growing. According to market research, photographing with phone cameras has become the most popular activity of smartphone owners, employed by 82% of users, which exceeds the next ubiquitous application, texting, which is utilized by 80% owners. Recent studies indicate that over a quarter of all digital photos have been taken with smartphones. The prevalence of smartphone cameras has been even more prominent on social photo sharing sites where the total count of posted images taken with smartphones has exceeded the cumulative count for stored photographs taken with any non-smartphone equipment.
Hundreds of millions smartphone users are increasingly blending their everyday digital lifestyles with paper habits in their business offices and homes. Paper documents retain a significant position in the everyday information flow of businesses and households. The role of digitizing and capturing paper based information has further increased with the arrival of unified multi-platform content management systems, such as the Evernote service and software developed by Evernote Corporation of Redwood City, Calif. Pages and excerpts from books and magazines, printed newspaper articles, receipts, invoices and checks, tax, financial, medical and other forms, printed reports, business cards, handwritten notes and memos on legal pads, in specialized Moleskine notebooks, on sticky notes or easels, and many other types of printed and handwritten documents are increasingly benefiting from digital capturing, storage and retrieval features of content management systems.
Modern scanners offer solutions for some of these information capturing needs. Accordingly, shipment volumes of mobile scanners are expected to grow from approximately one million to two million units in the next five years. Notwithstanding a growing scanner market, mobile lifestyles of workforce and consumers often requires capturing documents or portions thereof under random conditions where users may not have access to their office or home scanners. Additionally, some paper based formats, such as brochures and books, cannot be captured by sheet-fed scanners and often lack sufficient image quality when captured by flatbed scanners.
The aforementioned limitations have stimulated the development of smartphone based document capturing solutions, such as remote check deposit software or the Scannable software application by Evernote. A new breed of document capturing applications includes advanced algorithms for lighting, color and shape corrections, page border detection, contrast optimization, noise removal and other features aimed at creating optimized images of photographed documents nearing scan quality.
An especially useful time-saving feature of new smartphone applications is automatic scanning where the application detects subsequent pages of a document and takes snapshots of such pages without user intervention. In spite of early achievements in automatic scanning by smartphones, the efficiency of existing methods is still insufficient; scanning smartphone applications may significantly delay automatic shooting of document pages and often cause users to switch to a manual snapshot mode.
One challenge in automatic document scanning with smartphones is related to detecting document pages and pieces of content within pages. In contrast to traditional scanning when the scanned object is known to be a page and is correctly oriented along the coordinate axes, scanning with a smartphone camera introduces significant variations in the scene when a document page may be combined with other objects, slightly rotated, viewed under different angles and with perspective correction, blended with a scene background, etc. Hence, page and content boundaries aren't easily defined by the default conditions of captured images.
Accordingly, it becomes increasingly important to develop efficient methods for detecting page and content boundaries automatic scanning of document pages with smartphone cameras.